Cellulose is an organic compound that is the second most abundant in nature next to coal. It is the main component of the cell walls of higher plants. Cotton has a cellulose content of 98%, and fibers such as flax hemp fiber and hemp fiber have a cellulose content of about 70%. Cellulose is a straight-chain polymer compound, and the purest cellulose can be obtained by degreasing cotton fibers and boiling the degreased cotton fibers in dilute alkaline aqueous solution and is a white, odorless, water-insoluble solid. Large numbers of cellulose molecules form fibers composed of micelles that have a crystalline structure having a diameter of 0.05 nm or more and a length of 0.6 nm or more. The micelles are connected to each other by amorphous regions.
Unlike plant-derived cellulose, bio-cellulose produced by microorganisms or microbial cellulose does not contain impurities such as lignin or hemicellulose other than cellulose. Bio-cellulose is based on β-1,4 glucan and has a three-dimensional network structure composed of fibrils having a diameter of 20-50 nm. Owing to this structure, bio-cellulose has wetting properties, water absorbing properties, high strength and high resilience. In addition, bio-cellulose can be used as advanced materials, such as high-strength industrial materials, composite fibers, medical materials, and enzyme immobilization materials, by improving the productivity of bio-cellulose-producing strains and establishing the genetic manipulation conditions and culture conditions of the strains.
This bio-cellulose is based on glucose, and thus is likely to be contaminated by fungi or bacteria, which include cellulase genes, during transport and production. For this reason, it is difficult to use this bio-cellulose for industrial purposes. To facilitate transport and production and prevent contamination, dry bio-cellulose has been used. However, the time required to gel dry bio-cellulose is from several hours to several days depending on the content of cellulose. Thus, there has been a need for the development of a dry bio-cellulose that is quickly gelled.